respiration

American  

[res-puh-rey-shuhn] / ˌrɛs pəˈreɪ ʃən /

noun

1. the act of respiring; inhalation and exhalation of air; breathing.

2. Biology.

   1. the sum total of the physical and chemical processes in an organism by which oxygen is conveyed to tissues and cells, and the oxidation products, carbon dioxide and water, are given off.

   2. an analogous chemical process, as in muscle cells or in anaerobic bacteria, occurring in the absence of oxygen.

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respiration British  

/ ˌrɛspəˈreɪʃən /

noun

1. the process in living organisms of taking in oxygen from the surroundings and giving out carbon dioxide ( external respiration ). In terrestrial animals this is effected by breathing air

2. the chemical breakdown of complex organic substances, such as carbohydrates and fats, that takes place in the cells and tissues of animals and plants, during which energy is released and carbon dioxide produced ( internal respiration )

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respiration Scientific  

/ rĕs′pə-rā′shən /

1. The process by which organisms exchange gases, especially oxygen and carbon dioxide, with the environment. In air-breathing vertebrates, respiration takes place in the lungs. In fish and many invertebrates, respiration takes place through the gills. Respiration in green plants occurs during photosynthesis.

2. See cellular respiration

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respiration Cultural  

1. The conversion of oxygen by living things into the energy by which they continue life. Respiration is part of metabolism.

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Discover More

Carbon dioxide is a waste product of respiration.

Other Word Forms

• prerespiration noun
• respirational adjective

Etymology

Origin of respiration

1400–50; late Middle English respiracioun < Latin respīrātiōn- (stem of respīrātiō ) a breathing out, equivalent to respīrāt ( us ) (past participle of respīrāre to respire ) + -iōn- -ion

Example Sentences

In “Grass Breathing,” Mendieta, hidden beneath squares of sod, uses her own respiration to animate the earth above.

From The Wall Street Journal • Mar. 15, 2026

Cancer cells experience reduced respiration, DNA damage increases, and the cell cycle stops.

From Science Daily • Mar. 12, 2026

The compound is absorbed mainly by specific cancer cells, where it disrupts critical biological functions including cellular respiration and DNA production.

From Science Daily • Mar. 12, 2026

Unlike previous missions, these landers will have sensors specifically designed to "measure seafloor respiration", Sweetman explained.

From Barron's • Jan. 20, 2026

The long latent period of most cancers is the time required for the infinite number of cell divisions during which fermentation is gradually increasing after the initial damage to respiration.

From "Silent Spring" by Rachel Carson